FL4K the Beastmaster has always been one of the most versatile Borderlands 3 characters, with his ability to match his three powerful Action Skills with a unique and loyal companion creature.

Rakk attack:
Primary Skill Tree: Hunter
Build Focus: Long-Range/Sniper Prowess, High Action Skill Damage
Best Skills for Class Mods: Two F4ng (Highly Recommended), Grim Harvest (Highly Recommended), Interplanetary Stalker, Ambush Predator, Overclocked
Constantly active ASE anoints + you can spam rakks for decent damage + ASE 200% splash anoint increasing the damage of both your weapon and rakks by a significant amount = potentially the highest damage build. But the squishiest with no real survivability as the healing the rakks provide isn't enough. Rakks when paired with action skill start shield break anointed stop-gap or frozen heart give great survivability at the cost of a part of your damage.
Fade away:
Primary Skill Tree(s): Hunter & Stalker
Build Focus: Extreme Gun Damage & Crit Damage
Best Skills for Class Mods: Persistence Hunter (Highly Recommended), Head Count (Highly Recommended), Two F4ng, Big Game, Furious Attack, Overclocked
Lies in-between rakks and gamma burst imo, and is a good balance of damage and tankiness. With fade away end pet taunt and green tree's solid health regen, if you properly cycle fade away you can stay out of enemy attention most of the time, while doing great damage.
Gamma burst:
Primary Skill Tree(s): Master & Stalker
Build Focus: Strong Solo Play, High Pet Damage & Survivability
Best Skills for Class Mods: Ferocity, Frenzy, Pack Tactics, Eager To Impress, Hidden Machine
The tankiest setup but the one with least damage out of the three (which is still great damage since it's FL4K). With red fang pet taunt you'll never be targeted by enemies, which makes even the most difficult content in the game a breeze. Since you are never being targeted you can use the urad setup (150% rad damage when below 50% health) to improve your damage, but will still fall behind in damage when compared to rakk and fade away setups.
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